I have some customers rumoured to be gangsters, I dont know if they are and I mind my own business. They always pay cash and on time, they are always polite never use threatening behaviour. I make sure that whoever goes does nothing to upset them unless they want to end up swimming with the fishies LOL.
They also recommend us a lot too, we did a CCTV job for a second hand car dealer they had recommended us to. I was told that the car lot had had a few cars vandalised, when I turned up for the survey two of the cars were still on fire.